Conventionally, intensity modulation devices included liquid crystals and tiltable mirrors. Such intensity modulators have disadvantages in that light throughput efficiency and light power handling capacity are insufficient and stray light noise is too high. In particular, the liquid crystal display suffers most greatly regarding the light throughput efficiency and light power handling capacity, while the tilting micromirrors suffer from stray light noise.
In addition, although conventional intensity modulation devices such as liquid crystals are well-suited for large applications, they are not particularly well-suited for regulating the intensity of light on a microscopic scale. Rather, their large size renders them incapable of efficiently operating to block incident light in applications requiring fine precision intensity regulation on a small scale.
In the absence of a device capable of regulating the intensity of light on a microscopic scale, microscopic devices requiring such light regulation have generally relied upon pulsed laser light. Similarly, to digitalize conventional devices that are optically driven without increasing the size of those devices, pulsed laser light has been relied upon. For instance, when printing devices are digitalized, laser diodes have been conventionally used to regulate laser beams incident upon special paper where images are to be formed.
However, disadvantages frequently result when laser beams are required. For instance, when digitalizing printing devices as described above, an expensive type of special paper is required for printing and power consumption of the printing device must be increased to generate laser beams.